1. Field of the Invention
The present invention relates to a squeegee roller cleaning apparatus of a liquid electrophotographic printer and, more particularly, to a squeegee roller cleaning apparatus of a liquid electrophotographic printer having an improved structure so that hold-up volume developer remaining at a portion where a blade and squeegee roller contact each other is removed after a drip-line removal mode.
2. Description of the Related Art
In a typical liquid electrophotographic printer, as shown in FIG. 1, a photoreceptor web 10 that is a photoreceptor medium is supported by a plurality of guide rollers 11 to circulate along an endless path. The surface of the photoreceptor web 10 is charged by a charger 12 to the electric potential of about 600 V. The surface of the photoreceptor web 10 charged as above is converted to a predetermined electric potential (about 250V) by light emitted from a plurality of laser scanning units 13 so that an electrostatic latent image is formed thereon. A plurality of development units 20 for developing the electrostatic latent image with developer is installed to form a predetermined gap (hereinafter, referred to as a development gap) between the photoreceptor web 10 and each development unit 20. The development unit 20 also includes a development roller 22 maintaining an electric potential of about 450V. Charged developer is injected into the development gap by an injector (not shown). As the electric potential of the developer is lower than that of the development roller 22, the developer is transferred to an area where the electrostatic image is formed and adheres thereto.
The developer adhering to the electrostatic latent image area due to the difference in electric potential is squeezed by a squeegee roller 24 so that toner in the developer becomes filmy and is converted to a toner image. The remainder of the developer, other than the filmy toner, is removed by being squeezed from the photoreceptor web 10. Here, the toner image is dried by a drying unit 15. Also, the toner image is transferred from the photoreceptor web 10 to a transfer roller 16 due to the difference in surface energy between the transfer roller 16 and the photoreceptor web 10. The toner image on the surface of the transfer roller 16 is printed on the surface of a print paper P passing between the transfer roller 16 and a fixation roller 17.
After the development mode, as shown in FIG. 2, the development roller 22 is lowered to remove the developer, or drip-line developer D, remaining on the photoreceptor web 10 between the development roller 22 and the squeegee roller 24. Then, the squeegee roller 24, while being in contact with the photoreceptor web 10, is rotated opposite the direction in which the photoreceptor web 10 travels. As a result, the drip-line developer D is removed from the photoreceptor web 10 and the removed drip-line developer flows along the outer circumference of the squeegee roller 24 and is removed by a squeegee blade 26 contacting the surface of the squeegee roller 24.
However, after the drip-line removal mode, as shown in FIG. 3, the developer at a portion where the squeegee roller 24 and the blade 26 contact each other is not clearly removed so that a small amount of remaining developer referred to as hold-up volume developer B remains unnecessarily.
The blade 26 linearly contacts the squeegee roller 24 in a lengthwise direction. Thus, as shown in FIG. 4, the hold-up volume developer B remains on the surfaces of the blade 26 and the squeegee roller 24 even when the blade 26 is separated from the squeegee roller 24. The leftover developer remaining on the surface of the squeegee roller 24 is hardened thereon and transferred to the photoreceptor web 10 at the next development mode to contaminate the photoreceptor web 10 as well as the transfer roller 16 of FIG. 1.